merge from git-annex

Note that the batchCommand stuff is not used in git-repair, so
configure does not need to check for nice, ionice, and nocache,
nor are they dependend on.

1 files changed, 6 insertions, 0 deletions

diff --git a/Git/Ref.hs b/Git/Ref.hs
index 6ce1b87..0947293 100644
--- a/Git/Ref.hs
+++ b/Git/Ref.hs
@@ -10,6 +10,7 @@ module Git.Ref where
 import Common
 import Git
 import Git.Command
+import Git.Sha
 
 import Data.Char (chr)
 
@@ -105,6 +106,11 @@ matchingUniq refs repo = nubBy uniqref <$> matching refs repo
   where
 	uniqref (a, _) (b, _) = a == b
 
+{- Gets the sha of the tree a ref uses. -}
+tree :: Ref -> Repo -> IO (Maybe Sha)
+tree ref = extractSha <$$> pipeReadStrict
+	[ Param "rev-parse", Param (show ref ++ ":") ]
+
 {- Checks if a String is a legal git ref name.
  -
  - The rules for this are complex; see git-check-ref-format(1) -}